1. Field of the Invention
The present invention relates to a developing device for use in an image forming apparatus such as a printer or a copying machine.
2. Description of the Related Art
In this kind of developing device, various types are known. A typical example of known developing devices comprises a developing roller which rotates; a developing sleeve, the circumference of which is longer than that of the developing roller, loosely mounted on the peripheral surface thereof; a pair of guide members for pressing both end portions of the developing sleeve against the developing roller so that the rotational force of the developing roller is transmitted to the developing sleeve; and means for forming a thin layer of a developing toner on the peripheral surface of the developing sleeve.
The developing sleeve of this device has no irregularities on the inner peripheral surface, or smooth even though fine irregularities formed on the outer peripheral surface thereof so as to transport toners efficiently.